Hazard, and position markers are normally used to indicate that a problem is nearby, and individuals should either stay away or proceed with caution. Additionally these devices are also deployed to indicate a specific location (i.e. a lost person in the wilderness, a police or a military check point, or even a target location). The most common problems are vehicle accidents or breakdowns. Some of the reasons for using hazard markers in these situations include the protection of the people involved in the accident or breakdown and discouraging other people from driving or walking into the problem area. They are also used to discourage people from intruding into areas where emergency medical personal are treating injuries resulting from the accident or other personal are cleaning up the debris from the accident. Currently the most widely used hazard markers are sulfur based burning flares, large sequentially illuminated arrows, message signs, wooden barricades with a flashing light, and orange cones and barrels.
While the flare has an advantage of being easily visible both during the day and after dark, it also has the numerous disadvantages i.e. temporarily blinding motorists who drive by them after dark. This situation endangers the motorist and the people involved in the accident or breakdown. Another more serious problem exists when flares are used at the scene of an accident which has resulted in the spillage of gasoline, or other flammable fluids, or in an area that has local brush or other flammable ground cover. Other undesirable aspects of the flare include the risk of the person igniting the flare being burned and having their clothes burned, as well as the frequent deployment requirement due to their short burn time. Flares also release noxious fumes, and environmental contaminants while burning.
Orange cones or barrels are other popular hazard markers. They frequently have a blinking light attached thereto. A disadvantage of these is that the light cannot be readily seen outside of the immediate vicinity of the cone or barrel, especially in poor weather conditions. An additional problem associated with the cone, or marker light is that there are normally a directional marker only visible from a single view point, additionally in order for this type of marker to be visible they are dependent on size. This makes this device require a larger storage area, and makes their deployment difficult. Another problem with these hazard markers is that the light is frequently destroyed or severely damaged whenever the cone or barrel is inadvertently struck by a passing motorist, additionally the size of the device is large and when struck not only is the device normally damaged, but the unit itself becomes a projectile and can cause damage to property, as well as cause personal injury.
Flares are typically used in the boating industry to indicate a vessel in peril. While being highly visible they also pose a very serious problem. Normally a vessel in peril is not moving and the opportunity for gasoline vapor accumulation is great. Also, once a flare is lit is must be held over the side of the boat to prevent the hot molten material from the flare from damaging the boat which is usually made from fiberglass or has a fiberglass outer coating. As a result the flare cannot be set down and left unattended like normally done in a roadside situation.